PBI Puts Polar Bear Scientists on Film
Dr. Ian Stirling Click the image to enlarge.
Polar bears and climate change are in the news these days, with a retreating ice pack and thinner polar bears causing concern. To help the public sift through the media reports and understand the changes in the Arctic, PBI has embarked on a DVD project, "In Their Own Words," in which key polar bear scientists discuss the bears and the Arctic ecosystem. The series will be provided to educators free of charge as part of our Polar Bear Awareness program. It will also be available on our Web site for viewing by the general public. Watch the DVD online in our Gallery: Part 1 & Part 2.
"We believe that these top polar bear scientists need to be heard so that people understand the challenges that face the Far North and polar bears," says Robert Buchanan, PBI's president.
Filmmaker Karen Berkman, producer and director of Light Fantastic Films in Australia, donated time and production expenses to interview the first two scientists in the series, Dr. Ian Stirling of the Canadian Wildlife Service and Dr. Andrew Derocher of the University of Edmonton. After the first DVD is complete, she will interview Alaskan scientists. Following are excerpts from the first part of the series.
Changes in Hudson Bay
Dr. Ian Stirling has been studying the Hudson Bay population for over 30 years. He notes that the average date of the ice break-up now takes place about three weeks earlier than it did before, leaving the bears with a shorter hunting season.
Stirling explains that the Hudson Bay bears are forced ashore each summer when the ice on the bay disappears. The landlocked bears spend the next four months living off their fat reserves. "The amount of fat that they're able to put on is critical," Stirling says. "If the ice breaks up earlier, they have a progressively shorter period of time in which to lay on those stores."
He notes that cubs, subadults, and elderly bears are particularly vulnerable to a shorter hunting season. "There's a direct relationship between the date of the ice break-up and survival," he says. "One of the things that we're finding is that the health—or condition—of the bears has steadily declined over the last 30 years."
Stirling says that the Western Hudson Bay population has dropped by 22% since 1987. He predicts that unless the climate stabilizes or starts cooling again, there won't be many polar bears left in the area in 30 or 40 years.
Drownings in Alaska
Stirling sees the Hudson Bay population as part of a larger picture of Arctic climate change. Beaufort Sea bears, for example, including the four drowned bears recently found off the coast of Alaska, are also feeling the effects of warmer temperatures.
“There's a direct relationship between the date of the ice break-up and survival.”
- Dr. Ian Stirling
The scientist explains that the minimum ice-to-land distance used to be about 100 kilometers (60 miles). "Now it's 200 to 300 kilometers," he says. "Swimming 100 miles is not a big deal for a polar bear, especially a fat one. They just kind of float along and kick. But as the ice gets farther out from shore, it's a longer swim that costs more energy.
"The distance also leaves the bears more vulnerable. When there's a lot more water, there's a lot more fetch [surface area] for a storm to build up with big waves and rollers. The point is that the bears were out there in a big storm and what we saw is what we predicted would happen."
"We believe that these top polar bear scientists need to be heard so that people understand the challenges that face the Far North and polar bears," says Robert Buchanan, PBI's president.
Filmmaker Karen Berkman, producer and director of Light Fantastic Films in Australia, donated time and production expenses to interview the first two scientists in the series, Dr. Ian Stirling of the Canadian Wildlife Service and Dr. Andrew Derocher of the University of Edmonton. After the first DVD is complete, she will interview Alaskan scientists. Following are excerpts from the first part of the series.
Changes in Hudson Bay
Dr. Ian Stirling has been studying the Hudson Bay population for over 30 years. He notes that the average date of the ice break-up now takes place about three weeks earlier than it did before, leaving the bears with a shorter hunting season.
Stirling explains that the Hudson Bay bears are forced ashore each summer when the ice on the bay disappears. The landlocked bears spend the next four months living off their fat reserves. "The amount of fat that they're able to put on is critical," Stirling says. "If the ice breaks up earlier, they have a progressively shorter period of time in which to lay on those stores."
He notes that cubs, subadults, and elderly bears are particularly vulnerable to a shorter hunting season. "There's a direct relationship between the date of the ice break-up and survival," he says. "One of the things that we're finding is that the health—or condition—of the bears has steadily declined over the last 30 years."
Stirling says that the Western Hudson Bay population has dropped by 22% since 1987. He predicts that unless the climate stabilizes or starts cooling again, there won't be many polar bears left in the area in 30 or 40 years.
Drownings in Alaska
Stirling sees the Hudson Bay population as part of a larger picture of Arctic climate change. Beaufort Sea bears, for example, including the four drowned bears recently found off the coast of Alaska, are also feeling the effects of warmer temperatures.
“There's a direct relationship between the date of the ice break-up and survival.”
- Dr. Ian Stirling
The scientist explains that the minimum ice-to-land distance used to be about 100 kilometers (60 miles). "Now it's 200 to 300 kilometers," he says. "Swimming 100 miles is not a big deal for a polar bear, especially a fat one. They just kind of float along and kick. But as the ice gets farther out from shore, it's a longer swim that costs more energy.
"The distance also leaves the bears more vulnerable. When there's a lot more water, there's a lot more fetch [surface area] for a storm to build up with big waves and rollers. The point is that the bears were out there in a big storm and what we saw is what we predicted would happen."